Medical care of the outpatient is rapidly changing because of the aging population, increased prevalence of chronic disease, increased emphasis on collaborative care, and unrelenting pressure to reduce costs. To support the shift from the traditional episodic paradigm of care to the new continuous paradigm of care, physicians and patients need better tools for patient-doctor communication, patient-directed care outside of the clinic, and coordination of the care directed by patients and medical professionals. The increased availability of the Internet, wide acceptance of email, and proliferation of electronic medical records (EMRs) offer patients and physicians new opportunities to collaborate on improving the quality of outpatient care and enhancing medication safety. This application will address the impact on patient care and safety of tools for electronic patient-provider communication and shared online health records. Four related questions will be asked: 1) Is medication safety improved with patient prompts and a shared patient/physician EMR medication list? 2) Do patient prompts, reminders, and EMR entries improve chronic disease outcomes and adherence to guidelines in health care maintenance and chronic disease? 3) Does a prompted patient family history assessment improve detection of familial risk factors? 4) How does electronic communication and the shared use of the EMR by patients and physicians impact on medical practice, and how might barriers be addressed? These questions will be addressed by a randomized prospective cohort study of patients and providers who share health information using a secure, collaborative, Web-based electronic medical record and communication system.